Gas-operated automatic firearm



' Aug. 19, 1941. J. E. BRowNlNG .y y GAS-OPERATED AUTOMATIC FIREAM FiledAug. 31, 1958 QFWWAM@ a l u l Patented Aug. 19, 1941 UNITED STATESPATENT OFFICE GAS-OPERATED AUTOMATIC FIREARM Jonathan E. Browning,lOgden, Utah, assignor, by mesne assignments, to Western CartridgeCompany, a corporation of Delaware Application August 31, 1938, SerialNo. 227,713

9 Claims.

appreciably lessened in its effect upon the marks.

man.

Another object of the present invention is to provide a simple, reliableand effective organization of parts in a gas-operated automatic rearm,whereby compactness and low cost of manufacture are achieved.

A further object is to provide a'superior gasoperated automatic firearmin which a piston is employed for operating the action of the firearmand in which the impulse imparted to the said piston by the burning orburnt gases is automatically diminished to a very marked degree as thepiston approaches the limit of its travel under the impulse of the saidgases.

Still another object of the present invention is Fig. 4 is a transversesectional view taken on the line 4-4 of Fig. 2;

Fig. 5 is a. similar view taken on the line 5-5 of Fig. 3;

Fig. 6 is a perspective view of the tubular-piston together with aportion of the actuating-rod connected thereto;

Fig. 7 is a perspective view of the cylinder detached; and

Fig. 8 is a perspective view of the guard-tube detached.

For the purpose of illustration, a gas-operated automatic rifle has beenchosen for illustration g vin the accompanying drawing and will behereto provide a superior gas-operated automatic firef' arm whereinprovision is made to enable the gases which actuate the piston to set upcounter-recoil forces to measurably offset the recoil initiated by thedischarge of a cartridge.

With the above and other objects in View, as will appear to thoseskilled inthe art from the present disclosure, this invention includesall features in the said disclosure which are novel over the prior artand which are not claimed in any separate application.

In the accompanying drawing, in which certain modes of carrying out thepresent invention are shown for illustrative purposes:

Fig. 1 is a broken view partly in side elevation and partly in verticalcentral-longitudinal section of one form which a gas-operated automaticfirearm may assume in accordance with the present invention;

Fig. 2 is a fragmentary view on a larger scale ao Y inafter described indetail. .v

The automatic rifle illustrated in the accompanying drawing includes abarrel I0 having the usual axial bore II and rigidly 'attached at itsrear end to a receiver I2.' Attached to the barrel I0 and the receiverI2 is a stock I3 preferably formed of wood or other heat-insulating andshock-absorbing material, Reciprocating in an oblique path with respectto the axis of the barrel I0 and yalong the side of the receiver I2, isan action-slide I4 having a rearwardly-extending spring-plunger I5encircled by a helical breech-bolt-closing spring I6 acting toyieldingly urge the said action-slide I4 and connected parts forwardly.The forward end of the action-slide I4 is pivotally connected by meanslof a screw-stud I'I to the rear head I8 of an actuating-rod I9. Thesaid actuating-rod I9 reciprocates beneath the barrel IB and extendsthrough a vclcarence-passage 20 formed in a barrel-lug 2I and through anadjacentlearancegroove 22 formed in the stocky I3. The rear portion ofthe actuating-rod I 9 together with its rear head II8 and the forwardportion of the action-slide I4 reciprocates in an upwardly-apeningpocket 23 also formed in the stock I3 and communicating at its forwardend by the clearance-groove 22 already referred to.

The stock-attaching lug 2| above referred to extends downwardly into a.socket 2ia. extending than Fig. 1 and partly in side elevation and vpartly in vertical central-longitudinal section of the portion of thefirearm immediately adjacent the piston'and cylinder thereof;

Fig. 3 is a view corresponding to Fig. 2 but showing the piston movedrearwardly under the force of gas pressure to effect the actuation ofthe firearm-action;

downwardly from the bottom of the clearancegroove 22. Extending upwardlythrough an escutcheon 24 mounted in the under-face of the stock I3 is ascrew 25 threaded into the lower portion of the stock-attaching lug 2|.

As will be seen by reference to Fig. 1 the rear end of the action-slideI4 'has pivotally connected to it the lower end of abreechLbolt-operating link 26. The said link 26 has itis upper endpivotally connected to the lower rear portion of a breechbolt 21 movableWithin the 'receiver I2.

For the purpose of enabling the action-slide I4 and associated parts tobe manually operated the said action-slide has pivotally connected to itby means of a stud 29, the relatively-short vertical arm 29 of anL-shaped link 30. The said L-shaped link also includes a relatively-longsubstantially-horizontal arm 3i which is provided at itsrear end with anoperatinghandle 32 and which reciprocates in a guide-way 33 formed inlthe side wall of the receiver I2.

Secured in any suitable manner to the under portion of the receiver I2is a trigger plate 34 formed with a loop-like trigger guard 35 in whichis located a. trigger 36 controlling the ring of the automatic rifle inany suitable manner not herein requiring detailed description as forinstance, is more fully set forth in my copending application Ser. No.136,523 led April 13, 1937.

Returning now to the actuating-rod I9 before* referred to, it will benoted that the forward end thereof is pivotally connected by means of arivet 31 or the like to a bifurcated ear 38 projecting rearwardly fromthe lower portion of a tubular-piston 39. The tubular-piston 39 justreferred to, encircles the barrel III adjacent the forward end thereof.The internal diameter of the tubular-piston 39 and the external diameterof the adjacent portion of the barrel I are so related as to provide forthe smooth and relatively free sliding t required to permit the saidtubular-piston to reciprocate freely on the said barrel.

Immediately forwardly of the foremost position of the piston 39, thebarrel I0 is provided with an externally-threaded portion 40 onto whichis threaded the internally-threaded forward portion 4I of a cylinder 42.The said cylinder 42 is provided with a. rearwardly-extending annularskirt 43 having an internal diameter proportioned to receive with a freesliding fit, the tubular-piston 39 before referred to. As thusconstructed and arranged the interior surface of the skirt 43 of thecylinder 42 is uniformly spaced outwardly from the periphery of theadjacent portion of the barrel I0 so as to provide a gas-chamber 44 oftubular form and in which the tubular-.piston 39 is normally located.

The outer rear portion of the skirt 43 of the cylinder 42 is cut away toprovide an annular groove 45 in which fits the forward portion of aguard-tube 46 which is preferably formed of sheet metal and providedwith a plurality of vent-openings 41. The rear end of the guardtube 46yis in seated engagement with the forward portion of the stock I3 as isshown in Fig. 1. The said guard-tube 46 is provided in its lower portionwith a depressed or outwardlypressed portion resulting in the formationof a trough 48 ,provided for the clearance of the forward portion of theactuating-rod I9 and the bifurcated ear 38 of the tubular-piston 39.

Leading radially outwardly from the bore II of the barrel IU to theperiphery of the said barrel at apoint intersecting the forward end ofthe gas-chamber 44 and in registry with a notch 49 in the tubular-piston39 is a gas-port 50 The effective cross-sectional area of the outer endof the gas-port 50 just referred to, may be varied as desired bythreading the cylinder 42 rearwardly or forwardly to cover or uncover agreater or lesser extent of the said gals-port,

y:(Forconvenience of description the breechbolt 21 and its associatedparts which are actuated or motivated by the action-slide I4, may beconsidered as constituting the so-called "action l breech-bolt-closingspring of the rearm the casing of the cartridge which of the firearmherein chosen for illustration. in accordance with well understoodterminology in the art.

In order that the operation of the automatic fire-arm above describedand illustrated in the accompanying drawing may be understood, let it beassumed that the nre-arm is loaded preparatory to being red and that thetubular-piston 39 is in its forward position as illustrated in Figs. 1and 2 of the accompanying drawing.

If now the trigger 36 is operated, the cartridge in thecartridge-chamber of the firearm will be discharged with the result thatthe projectile will be propelled forwardly through the bore II of thebarrel IU under the force of the burning powder charge. As theprojectile passes beyond the inner end of the gas-port 5U, the gasunderpressure back of the said projectile will escape radially outwardlythrough the said gas-port 5I) into the tubular gas-chamber 44. The entryof gas into the forward portion of the tubular gas-chamber 44 willresult in the tubular-piston 39 being kicked" so to speak, rearwardlythus causing the actuating-rod I9, action-slide I4, breech-bolt 21 andassociated parts to be moved rearwardly against the counter-urge of theI6. By this operation has just been fired will be ejected and the firingmechanism will be cocked preparatory tothe return movement of thebreech-bolt 21, actionslide I4 and associated parts to their formerpositions in which they are illustrated Figs. 1 and 2.

In its rearward movement the tubular-piston 39 will ride completely outof the gas-chamber 44 and out of engagement with the skirt 43 of thecylinder 42 with the result that there will be a sudden release of gaspressure from the said gas-chamber 44. The gas escaping from thegas-chamber 44 when the tubular-piston 39 moves rearwardly as justdescribed, will travel rearwardly in the space between the barrel I0 andthe inner surface of the guard-tube 46 and thence outwardly through thevent openings 41 therein with the effect of producing a counterrecoileffect measurably offsetting or softening the total effect of the recoiloccasioned by the initial ring of the rearm.

In addition the counter-recoil eiect above referred to the rearwardmovement of the tubularpiston 39 completely out of the gas-chamber 44 inthe cylinder 42 will cause a marked diminution in the force applied tothe said tubularpiston during the latter part of its rearward movement,thus enabling the said piston to slow down at a much greater rate thanwould be the case were the gas pressure applied to the front end of thepiston to be permitted to continue the active propulsion of the saidtubular-piston throughout the entire rearward travel thereof. The effectjust described serves to provide maximum power to initiate the rearwardtravel of the breech-bolt 21 to effect the extraction of the cartridgecase of the just-fired cartridge. After the initial impulse imparted tothe breech-bolt 21 and associated parts. the rearward urge upon thetubular-piston 39 for a major portion of its rearward travel is somarkedly lessened as to automatically avoid without the use of complexmechanisms, the injury to the firearm-action and associated partsincident to their stoppage at the limit of their rearward travel priorto their forward travel back into the position in which they are shownin Figs. 1 and 2 preparatory to another cycle of operation of thefirearm.

In a manner common in automatic firearms the breech-bolt 21, afterhaving reached a limit of its rearward travel under the impulse impartedto it by the initial movement of the. tubular-piston 39, moves forwardlyunder the urge of the breech-bolt-closing spring I6 to effect theinsertion of a fresh cartridgel into the cartridge chamber of thefirearm, preparatory to the firing thereof.

The invention may be carried out in other specific ways than thoseherein set forth without departing from the spirit andessentialcharacteristics of the invention, and the present embodiments are,therefore, to be considered in al1 respects as illustrative and notrestrictive, and all changes 'coming within the meaning and equivalency,range of the appended claims are intended to beembraced therein.

I claim:

1. A gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston; operating-connections between thetubularpiston and the said firearm-action; a barrel extending throughthe hollow interior of the said tubular-piston and having a gas-portleading laterally from its interior to its exterior; and a cylindermounted upon the said barrel and having a cylindrical portionsurrounding the said barrel in radially-spaced relationship thereto andpro- 'viding a tubular gas-chamber therebetween in communication withthe said gas-port in the said barrel; the said operating-connectionsbeing operable to move the tubular-piston into the said tubulargas-chamber to,position the same therein; the said tubular-pistonpositioned in the gas-chamber being subject to the pressure of the gasto move outwardly with respect to the gaschamber, and the said tubulargas-chamber formed between the said cylinder and barrel being.y

materially shorter in a direction along the axis of the said barrel thanis the stroke of the said tubular-piston, whereby the saidtubular-piston in its travel moves out of the said gas-chamber andthereby permits the gas to freely escape from the said gas-chamber.

2. A gas-operated automatic flrearm, including in combination: afirearm-action; a tubularpiston; operating-connections between thetubular-piston and the said firearm-action; a barrel extending throughthe hollow interior of the said tubular-piston and having a gas-portleading laterally from its interior to its exterior; and a cylindermounted upon the said barrel and having a cylindrical portionsurrounding the said barrel in radially-spaced relationship thereto `andproviding a rearwardly-opening tubular gas-chamber therebetween incommunication with the said gas-port in the said barrel; the saidoperatingconnections being operable to move the tubularpiston into thesaid tubular gas-chamber to position the same therein; the saidtubular-piston positioned in the ,gas-chamber being subject to thepressure of th'e gas to move outwardly with respect to the gas-chamber,and the said rearwardly-opening gas-chamber formed between the saidcylinder and barrel being materially shorter in a direction yalong theaxis ofthe said barrel than is the stroke of the said tubular-piston,

whereby tlie said tubular-piston in its rearward y,

travel moves out of the said rearwardly-opening tubular gas-chamber andthereby permits the gas to freely escape from the said gas-chamber.

3. A gas-operated automatic firearm, including in combination: afirearm-action; a tubularpiston; operating-connections between thetubular-piston and the said firearm-action; a barrel extending throughthe hollow interior of the said tubular-piston; a cylinder mounted uponthe said barrel and having a cylindrical portion surrounding the saidbarrel in radially-spaced relationship thereto and providingtherebetween a rearwardly-opening tubular gas-chamber closed at theforward end thereof; gas-admitting means communicating with the forwardportion of the said gas-chamber for supplying gas under pressure theretofrom the interior of the said barrel; and a guard-tube surrounding thesaid barrel and extending rearwardly from the said cylinder thereof andproviding a channel around the said barrel for the accommodation of thesaid tubularpiston`and having a cross-sectional area materially greaterthan the cross-sectional area of the said tubular-piston; the saidtubular-piston being movable to pass from the said guard-tube into thesaid gas-chamber and into the said Iorward portion thereof adjacent thesaid gas-admitting means, the said tubular-piston being subject to thegas admitted to the gas-chamber to move rearwardly from the forwardportion thereof, and the said gas-chamber formed'between the saidcylinder and barrel being materially shorter in a direction along theaxis of the said barrel than is the stroke of the said tubularpiston,whereby the said tubular-piston in its travel rearwardly moves out ofthe said rearwardly-opening gas-chamber and into the saidrearwardly-extending guard-tube and thereby permits the gas to freelyescape from the said gas-chamber.

4. gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston; operatingconnections between thetubularpiston and the said firearm-action; a barrel extending throughthe hollow interior of the said tubular-piston and having a gas-portleading l terally from its interior to its exterior; a cylin er mountedupon the said barrel and having a cylindrical portion surrounding thesaid barrel in radially-spaced relationship thereto and providing atubular gas-chamber therebetween in cornmunication with ,thea/saidgas-port in the said barrel; the said o/per/ l erable to move rthetubular-piston into the said tubular gas-chamber to position the sametherein; and a guard-tube surrounding thesaid barrel adjacent to saidcylinder thereon and providing a channel around the said barrel fortheaccommodation of the said tubular-piston and having a cross-sectionalarea materially greater than the cross-sectional" area of the saidtubular-piston; the said tubular-piston positioned in the ,gaschamberbeing subjectlto the pressure of the gas to movef outwardly with respectto the gas-chamber, and the said gas-chamber formed between the saidcylinder and barrel being materially shorter in a direction along theaxis of the said barrel than is the stroke of the said tubularpiston,whereby the said tubular-piston in its travel moves out of the saidgas-chamber and into the said guard-tube and thereby permits the gas tofreely escape from the said gas-chamber.

5. A gas-operated/automatic firearm, including in combination:avfflrearm-action; a tubular-piston; operating-connections between thetubularting-connections being oppiston and the said firearm-action; abarrel extending through the hollow interior of the sont tubular-pistonand having a gas-port leading laterally from its interior to itsexterior; a cylin- Aviding a chamber around the said barrel for theaccommodation of the said tubular-piston and having a cross-sectionalarea materially greater than the cross-sectional area of the saidtubularpiston; the said tubular-piston positioned in the gas-chamberbeing subject to the pressure of the gas to move outwardly with respectto the gaschamber, and the said gas-chamber formed between the saidcylinder and barrel being materially shorter in a direction along theaxis of the said barrel than is the stroke of the said tubularpiston,whereby the said tubular-piston in its travel rearwardly moves out ofthe said rearwardly-opening gas-chamber and into the saidrearwardly-extending guard-tube and thereby permits the gas to freelyescape from the said gas-chamber.

6. A gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston provided in one edge with a notch;operating-connections between the tubular-piston and the saidfirearm-action; a barrel extending through the hollow interior of thesaid tubularpiston and having a gas-port leading laterally from itsinterior to its exterior; and a cylinder mounted upon the said barrelandhaving a cylindrical portion surrounding the said barrel inradially-spaced relationship thereto and providing a tubular gas-chambertherebetween; the said tubular-piston being movable to enter into thesaid gas-chamber and to be positioned therein with its said notchcommunicating with the Said gas-port; the said tubular-piston beingsubject to the pressure of gas admitted to the said gas-chamber, and thelatter being materially shorter in the direction of the barrel than thestroke of the piston, whereby the piston may be moved out of the saidgas-chamber and permit the escape of gas therefrom.

7. A gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston provided in one edge with a notch;operatingconnections between the tubular-piston and the saidfirearm-action; a barrel extending through the hollow interior of thesaid tubular-piston and having a gas-port leading laterally from itsinterior to its exterior; and a cylinder mountedl upon the said barreland having a cylindrical portion extending along a relatively-shortportion of and surrounding the said barrel in radially-spacedrelationship thereto and providing a tubular gas-chamber therebetweenhaving its forward portion communicating with the said gas-port; thesaid tubular-piston being movable to enter into the said gas-chamber andto be positioned in the forward portion thereof with its said notchcommunicating with the said gasport; the tubular-piston beingV subjectto the pressure of gas admitted to the said gas-chamber, and the saidrelatively-short portion of the cylinder providing a tubulargas-'chamber which is .materially shorter in axial direction than is thestroke of the said tubular-piston, whereby the said tubular-piston inits travel moves out of the said gas-chamber and thereby permits the gasto freely escape from the said gas-chamber.

8. A gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston having a notch in its forward edge;operating-connections between the tubular-piston and the saidfirearm-action; a barrel extending through the hollow interior of thesaid tubularpiston and having a gas-port leading laterally from itsinterior to its exterior; and a cylinder mounted upon the said barreland having a cylindrical portion surrounding the said barrel inradially-spaced relationship thereto and providing therebetween arearwardly-opening tubular gaschamber closed at the forward end thereof;the said tubular-piston being movable to enter into the said gas-chamberand to be positioned with the notch in the forward edge thereofcommunicating with the said gas-port; the said tubularpiston beingsubject to the pressure of gas admitted to said gas-chamber, and thelatter being materially shorter in the axial direction of the barrelthan is the stroke of the tubular-piston, whereby the tubular-piston maymove out of said gas-chamber and permit the escape of gas therefrom.

9. A gas-operated automatic firearm, including in combination: afirearm-action; a tubular-piston having a notch in its forward edge;operating-connections between the tubular-piston and the saidfirearm-action; a barrel extending through the hollow interior of thesaid tubularpiston and having a gas-port leading laterally from itsinterior to its exterior; and a cylinder mounted'upon the said barreland having a. cylindrical portion extending along a relatively-shortportion of and surrounding the said barrel in radially-spacedrelationship thereto and providing therebetween a rearwardly-openingtubular gas-chamber closed at the forward end thereof; the saidtubular-piston being movable into the said gas-chamber to bring thenotch in the forward edge of the tubular-piston into communication withthe said gas-port; the said tubularpiston' being subject to the pressureof gas ad mitted to said gas-chamber and the said relatively-shortportion of the cylinder providing a rearwardly-opening gas-chamber whichis materially shorter in a direction along the axis of the said barrelthan is the stroke of the said tubular-piston, whereby the saidtubular-piston in its rearward travel moves out of the saidrearwardlyopening tubular gas-chamber and thereby permits the gas tofreely escape from the said gaschamber.

JONATHAN E. BROWNING.

